Evidence suggests that the patient-centered medical home (PCMH) model of primary care improves management of chronic disease, but there is limited research contrasting this model's effect when financed by a single payer versus multiple payers, and among patients with different types of health insurance. This study evaluates the impact of a statewide medical home demonstration, the Maryland Multi-Payer PCMH Program (MMPP), on adherence to antihypertensive medication therapy relative to non-PCMH primary care and to the PCMH model when financed by a single payer. The authors used a difference-in-differences analytic design to analyze changes in medication possession ratio for antihypertensive medications among Medicaid-insured and privately insured non-elderly adult patients attributed to primary care practices in the MMPP ("multi-payer PCMHs"), medical homes in Maryland that participated in a regional PCMH program funded by a single private payer ("single-payer PCMHs"), and non-PCMH practices in Maryland. Comparison sites were matched to multi-payer PCMHs using propensity scores based on practice characteristics, location, and aggregated provider characteristics. Multi-payer PCMHs performed better on antihypertensive medication adherence for both Medicaid-insured and privately insured patients relative to single-payer PCMHs. Statistically significant effects were not observed consistently until the second year of the demonstration. There were negligible differences in outcome trends between multi-payer medical homes and matched non-PCMH practices. Findings indicate that health care delivery innovations may yield superior population health outcomes under multi-payer financing compared to when such initiatives are financed by a single payer.